1. Field of the Invention
The present invention relates to an exposure value adjustment apparatus, method, and non-transitory computer readable medium thereof; more specifically, the present invention relates to an exposure value adjustment apparatus, method, and non-transitory computer readable medium that utilizes the histogram of a reference image.
2. Descriptions of the Related Art
The techniques for generating High Dynamic Range (HDR) images have been investigated in recent years, which allow an image to have a greater dynamic range between the lightest and darkest areas of the image.
Conventional HDR techniques capture several images (e.g. three images) by different exposure values and then generate an HDR image based on these images. These conventional HDR techniques have drawbacks because environment conditions have not been considered. Specifically, conventional HDR techniques have no knowledge of how much under-expose value to recover enough highlights and/or how much the over-expose value to recover enough shadows. In ideal case, if the current image is adequately exposed, a setting such as +1 EV and −1 EV (or +2 EV and −2 EV) may be good for the next image. However, this is often not the case in our real life. For example, when the current image is under-exposed, a setting of −2 EV will only complicate the problem. Likewise, when the current image is over-exposed, a setting of +2 EV will complicate the problem as well.
Consequently, the technique for generating HDR images that takes the environment conditions into consideration is still in an urgent need.